Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9334f4d8e3a48ff…

MALICIOUS

PDF

75.7 KB Created: 2021-09-23 16:38:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 863581d4882cdc80f0f6bee765ff783c SHA-1: 98660357ae1f36d5d5c05dcea650d17e83c1332d SHA-256: b9334f4d8e3a48ff2f6b41b67af7e6e8469f33f2b8a3e233b965e6c188a2f2e6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting, which likely serve as a link farm to distribute further malicious content. The document body is heavily obfuscated and appears to be non-readable content generated by wkhtmltopdf, suggesting the primary function is to host these links rather than present user-facing information.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL https://coretry.ru/uplcv?utm_term=the+law+of+journalism+and+mass+communication+7th+edition+pdf PDF link annotation
    • http://yangpupark.com/uploadfile/files/54491144480.pdfIn PDF document text
    • https://srccaa.bdbabymart.com/app/webroot/ckfinder/userfiles/files/83700251720.pdfIn PDF document text
    • http://ipsaix.com/ckeditor/ckfinder/userfiles/files/95654013489.pdfIn PDF document text
    • http://yishiweb.com/upfiles/files/20210904_105850.pdfIn PDF document text
    • https://ripedesign.com/app/webroot/files/fckeditor/file/47688577390.pdfIn PDF document text
    • https://fietenhaardenenkachels.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16142422c7b112---46864430150.pdfIn PDF document text
    • https://elnativocoffee.com/silver/upload/files/kumubazutekajazijuxivuzip.pdfIn PDF document text
    • http://jar-ted.pl/file/baxut.pdfIn PDF document text
    • https://nppmaudaha.in/ckfinder/userfiles/files/76803546616.pdfIn PDF document text
    • https://oancora.com/ckfinder/files/29429252091.pdfIn PDF document text
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f61abf1b06---44226845758.pdfIn PDF document text
    • http://keifo.ru/ckfinder/userfiles/files/wexizevelefex.pdfIn PDF document text
    • https://grnca.org/img/files/files/lokutupoguvilisen.pdfIn PDF document text
    • https://greenvalleykerala.com/ckfinder/userfiles/files/11638236685.pdfIn PDF document text
    • http://educasters.co/ckfinder/userfiles/files/fimediziniwogefunuxefil.pdfIn PDF document text
    • https://swapnauraan.com/ckfinder/userfiles/files/zekavar.pdfIn PDF document text
    • https://icoachyou.biz/images/ckeditor/files/37312769793.pdfIn PDF document text
    • http://spbmedax.ru/sites/default/files/uploads/47336302540.pdfIn PDF document text
    • http://fsgpj.com/upfolder/e/files/20210911045322.pdfIn PDF document text
    • http://sooam.com/files/fckeditor/file/181386116061474e2be6d7e.pdfIn PDF document text
    • http://softtox.com/new/userfiles/file/botudilininaremesof.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/aomslk180vq4u5nkgiqd1kmko3/26673884276.pdfIn PDF document text
    • https://tavcam.com/upload/ckfinder/files/97400633220.pdfIn PDF document text
    • http://ecolservizinettuno.com/userfiles/files/74388181561.pdfIn PDF document text
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000c3d8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC3D8 16340 bytes
SHA-256: 23f5b2c46a9de3514bbc59d54c17b6372f87748e7d421c9def3c45cbcf983e9e
font_01_sfnt_off0000ee0f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE0F 11216 bytes
SHA-256: 4e6ab544cf7770bcf489358aaeb925e0500d5f712bd815e043490d3b5f946a11
font_02_sfnt_off00010840.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10840 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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